哮喘小鼠CD4＋CD25＋调节性T细胞及Foxp3表达的变化

Change of CD4＋CD25＋ regulatory T cell and expression of Foxp3 in a mouse model of asthma

目的探讨哮喘小鼠CD4＋CD25＋调节性T细胞数量的变化及相关转录因子F0xp3表达的变化。方法24只5周龄C57BL／6小鼠随机分为哮喘模型组和对照组，每组12只，于第0天和第14天，哮喘组以腹腔注射致敏液[0．1％的鸡卵蛋白（OVA）0．1ml与等体积液态铝混合]0．2ml致敏，对照组注射等体积生理盐水，第24、25、26天开始雾化吸入1％的OVA（哮喘组）或生理盐水（对照组）进行激发，连续3d，于最后1次激发后48h处死小鼠。取脾脏，制备脾细胞悬液，流式细胞术检测脾脏CD4＋CD25＋T细胞占CD4＋T细胞比例。取脾脏组织以RT-PCR和Western blot分别检测脾脏Foxp3mRNA和蛋白的表达。数据结果以Levene法行方差齐性检验后，进行独立样本的t检验，以P〈0．05为差异具有统计学意义。结果脾脏CD4＋CD25＋T细胞占CD4＋T细胞比例哮喘组为（7．03±2、19）％，对照组为（9．70±2．80）％，哮喘组低于对照组，两者相比差异有统计学意义（P=0．016）；脾脏Foxp3mRNA的表达水平哮喘组为（0．37±0．11），对照组为（0．237±0．118），哮喘组高于对照组，两者相比差异有统计学意义（P=0．1309）；脾脏Foxp3蛋白的表达水平哮喘组（0．692±0．171），对照组（0．515±0．135），哮喘组高于对照组，两者相比差异有统计学意义（P=0．01）。结论哮喘时抗原对CD4＋CD25＋细胞的激活不足，可能在哮喘发病机制中起一定作用。

Objective To investigate the change of CD4＋CD25＋ regulatory T cell and expression of Foxp3 in a mouse model of asthma. Method Twenty-four C57BL/6 mice were randomly divided into asthma group and control group. Mice in the asthma group were sensitized intraperitoneally with 0. 1 ml of 0. 1% OVA pins 0. 1 ml of alumintum hydroxide at 0 and 14 days. On the day 24, 25 and 26, inhaled withe 1% OVA for excitation, while control group were injected with saline solution. The animals were sacrificed 48 hours after the last OVA or saline for excitation. The spleen cells were harvested and the percentage of CD4 ＋ CD25 ＋ T cell in CD4 ＋ was detected with flow cytometer. The level of Foxp3 mRNA and protein expressio.： in spleen tissue were assessed by RT-PCR and Western blot respectively. Results The percentage of CD4＋CD25＋ T cell in CD4 ＋ was significantly lower in asthma group than that in control group [ （7. 03 ± 2.19） % vs （9.70 ± 2.80） %, P = 0.0163. The level of Foxp3 mRNA expression was significantly higher in asthma group than that in control group [ （0.37 ± 0.11） vs 0.237±0.118）, P = 0.009], and the level of Foxp3 protein expression was significantly higher in asthma group thanthat in control group [ （0.692±0.171） vs （0.515±0.135）, P=0.01]. Conclusions Insufficiency of CD4＋ CD25＋ T cell in response to allergen stimulation, may play an important role in the pathogenesis of asthma.